STING1 senses mitochondrial damage to promote mitophagy

The cGAS-STING1 pathway is essential for innate immunity, while its functions beyond immune activation have emerged as a key research topic. Recent studies have revealed the non-canonical roles of this pathway in autophagy. However, whether it participates in organelle quality control through selective autophagy processes such as mitophagy remains largely unexplored. In our study, we identify the cGAS-STING1 pathway as an essential upstream regulator of PINK1-PRKN-dependent mitophagy. We demonstrate that upon mitochondrial damage, STING1 is recruited to damaged mitochondria in a process requiring PINK1- and VCP/p97-mediated degradation of outer mitochondrial membrane proteins. STING1 at damaged mitochondria then activates TBK1, which phosphorylates the mitophagy receptor OPTN at Ser177, enhancing its recruitment to damaged mitochondria and driving efficient mitophagy. Disruption of the STING1-TBK1-OPTN axis impairs mitophagy and shifts the cellular response from pro-survival mitophagy to apoptosis. Our findings therefore uncover a non-canonical, pro-survival function of the cGAS-STING1 pathway in mitophagy, extending its role beyond innate immunity to the regulation of selective autophagy and cell fate decisions. Abbreviations: BafA1: bafilomycin A1; cGAS: cyclic GMP‑AMP synthase; ER: endoplasmic reticulum; GABARAP: GABA type A receptor-associated protein; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; MQC: mitochondrial quality control; mtDNA: mitochondrial DNA; NAC: N-Acetylcysteine; Nec-1: Necrostatin-1; OMM: outer mitochondrial membrane; OPTN: optineurin; PINK1: PTEN induced kinase 1; PRKN: parkin RBR E3 ubiquitin protein ligase; RIPK1: receptor interacting serine/threonine kinase 1; ROS: reactive oxygen species; STING1: stimulator of interferon response cGAMP interactor 1; TBK1: TANK binding kinase 1; TFEB: transcription factor EB; VCP/p97: valosin containing protein; Z-VAD-FMK: benzyloxycarbony (Cbz)-l-ValAla-Asp (OMe)-fluoromethylketone.